DE102007013092A1 - Apparatus and method for drying fluids circulated in closed circuits - Google Patents

Abstract

The invention relates to a device for drying fluids guided in closed circuits with a bypass line (20), which is switchable in parallel to a fluid-conducting tube (10) of the closed circuit via a first valve (V1) and a second valve (V2), wherein in the bypass line (20) a first dehumidifier (E1) is arranged. Furthermore, the invention relates to a method for drying fluids circulated in closed circuits, in which a fluid-conducting tube (10) of the closed circuit part of the fluid in a parallel to the fluid-conducting tube (10) of the closed circuit switched bypass line ( 20) is guided and wherein in the bypass line (20) a device for drying fluids according to one of the preceding claims is arranged.

Description

The The invention relates to a device for drying in closed cycles out Fluids and a process for drying fluids circulated in closed circuits.

In In various applications, fluids are conducted in closed circuits, wherein it is essential that the fluids are dry.

Humidity, especially water in refrigerant of refrigeration systems, makes a big one Problem for the functionality the refrigeration system On the one hand, icing and freezing can be more important Components come what is the coolant flow in derogation. On the other hand leads the water in combination with refrigerant oil for acid formation, what acidity and if necessary a burnout of one in the refrigeration system existing compressor may result. Therefore, it is necessary the water content in the refrigeration cycle to reduce and during the Operation of the system as possible to keep low.

Known is it, the whole Switch off refrigeration system, afterwards the entire in the refrigeration system existing refrigerant to remove and dispose of, to dry the plant with nitrogen and with dry refrigerant to refill again. One such method leads to that the refrigeration system over a longer time Completely stands still and results in high costs because of the refrigerant Completely exchanged and must also be disposed of.

Farther It is known in a the refrigerant leading Management of the refrigeration system, especially in front of a compressor, a dehumidifier in the form of a Install moisture filter. The refrigerant thus flows through the moisture filter, which filters out the moisture that thus enriched in the moisture filter. The moisture filter must be monitored to prevent the moisture filter from becoming completely saturated and a water breakthrough can occur. The moisture filter must thus regularly exchanged which also leads to downtime of the refrigeration system and with a high workload connected is.

The The object of the invention is therefore to provide a device and to provide a process for drying closed-loop fluids which is the continuous drying of fluid during operation of the closed cycle and thus a high time and Avoid cost.

The Task is solved according to the invention with a Apparatus for drying fluids circulated in closed circuits with the features of claim 1 and with a method for drying closed-loop fluids having the features of the claims 26 or 27.

advantageous Embodiments and developments of the invention are specified in the subclaims.

The inventive device drying of closed-loop fluids is based on to provide a bypass line, which via a first valve and a second valve parallel to a fluid-carrying tube of the closed Circuit is switchable. Part of the closed circuit flowing Fluids is thus directed into the bypass line. According to the invention is in the bypass line arranged a first dehumidifier, which the Fluid deprives the moisture. Because the dehumidifier is not anymore is arranged directly in the closed circuit, if the dehumidifier must be replaced, the bypass line over the first and second valves are closed towards the closed circuit, whereupon the dehumidifier is removed from the bypass line and against a new or cleaned dehumidifier can be replaced.

at An advantageous development of the invention is in the bypass line arranged a second dehumidifier behind the first dehumidifier, the second dehumidifier not being picked up by the first dehumidifier Moisture can absorb the effectiveness of drying the fluid to improve.

at a particularly preferred embodiment The invention is between the first valve and the first dehumidifier a third valve and between the second dehumidifier and the second Valve arranged a fourth valve, wherein via the third valve in the flow direction either the first dehumidifier or the second dehumidifier behind the valve is switchable and being alternative via the fourth valve either the second dehumidifier or the first dehumidifier before that second valve is switchable, so that when flowing from the third valve either the first dehumidifier to the fourth valve and then the second dehumidifier or alternatively the first second dehumidifier and then the first dehumidifier is flowed through.

The first and / or the second dehumidifier can be designed as a moisture exchanger, as a moisture filter or as a moisture filter with integrated moisture exchanger. In one embodiment, the first dehumidifier is designed as a moisture filter and the second dehumidifier as a moisture exchanger or else the first and / or second dehumidifier as a moisture filter with integrated moisture exchanger to in the Moisture filter initially enriched during operation of the closed circuit moisture in the moisture filter to then, when a certain degree of saturation of the moisture filter was reached to heat this example, and the humidity on the moisture without interference, in particular shutdown of the closed circuit or opening the bypass circuit after externally removed from the closed circuit and the bypass line. The moisture exchanger thus has the advantage that moisture can be removed from the closed circuit without downtime of the circuit from the closed circuit, the moisture exchanger for effective removal of water requires a certain gradient. This is achieved by combining the moisture exchanger with a moisture filter, which initially enriches the moisture and then delivers it selectively in larger quantities, so that a high gradient is produced at the moisture exchanger and the moisture exchanger effectively dissipates the moisture.

at a particularly preferred embodiment In the invention, the first and second dehumidifiers are wet filters trained while in between the two humidity filters another dehumidifier in the form of a additional Moisture exchanger is arranged. Especially with the possibility the flow direction to change through the bypass line, This construction gives the possibility to start in one of the two dehumidifiers, which is designed as a moisture filter are, for example, the first dehumidifier, a large part of Moisture save while the other, for example, the second dehumidifier the residual moisture filtered out of the fluid, and then upon reaching the degree of saturation the first dehumidifier this targeted to the water, for example by heating, then to move the moisture over the remove the first dehumidifier downstream humidifier, wherein the second dehumidifier will continue to hold the residual moisture that passes through the moisture exchanger not discharged will be able to filter out. Subsequently, the flow direction changed be so that the second dehumidifier out the bulk of the moisture withdraws the fluid, so that a total of the most effective drying and a maximum moisture removal can be achieved.

The fluid flows only past the moisture exchanger, it is in the Usually by very low water contents, so that the humidity gradient comparatively is small and the moisture exchanger does not work optimally or effectively can. Therefore, preferably facing away from the closed circuit Side of the moisture exchanger, a device for generating a Moisture gradients arranged. This device can in one embodiment be designed as a device for generating a negative pressure. Alternatively, the device is for generating a moisture gradient is formed as a desiccant feeder, which includes a Desiccant past the moisture exchanger in a desiccant removal leads. The desiccant may be, for example, air or nitrogen. Preferably, the desiccant on another device additionally dehumidified.

To is in a preferred embodiment between the desiccant feeder and the moisture exchanger a third dehumidifier arranged, the activity of the desiccant Feuch removes, so that the moisture gradient is increased at the moisture exchanger.

Preferably can enter between the moisture exchanger and desiccant removal be arranged fourth dehumidifier, which moisture, the was taken on the moisture exchanger of the desiccant and was withdrawn from the closed circuit, also from the desiccant remove again, especially if the desiccant again passed the moisture exchanger becomes.

In a particularly preferred embodiment of the invention, a fifth valve is disposed between the desiccant feeder and the third dehumidifier, and a sixth valve is disposed between the fourth dehumidifier and the desiccant discharge, wherein either the third dehumidifier or the fourth dehumidifier is switchable behind the desiccant supply means via the fifth valve in the flow direction and wherein via the sixth valve alternatively either the fourth dehumidifier or the third dehumidifier is switchable prior to the desiccant discharge, so that on flow from the desiccant supply means to the desiccant discharge either first the third dehumidifier and then the fourth dehumidifier or alternatively first the fourth dehumidifier and then the third dehumidifier is flowed through. Thus, a particularly effective drying of the desiccant as described above is also possible in the circulation of the desiccant. But even if the desiccant is not circulated, it is ensured by this design that basically a dehumidifier is located in front of the moisture exchanger in both flow directions, so as to ensure that dried desiccant is fed to the moisture exchanger and thus the moisture gradient is increased and on the other hand, for drying the dehumidifier each dehumidifier can be switched before the desiccant removal, so that when you heat the dehumidifier, the moisture can be passed directly to the desiccant removal, without being led past the moisture exchanger and there to reduce the moisture gradient or even moisture in the ge enter closed circuit of the fluid.

there In particular, in a preferred embodiment, the third and / or the fourth dehumidifier designed as a moisture filter.

The Moisture filters are preferably designed as zeolite filters to to ensure effective accumulation of moisture in the filter.

Around the moisture from the dehumidifiers without changing the dehumidifier drive out the various dehumidifiers are preferably heated. Out the same reason is also the additional humidity exchanger, if available, heated.

Of the Moisture exchanger is preferably a moisture-permeable membrane, in particular as a Nafion membrane or as zeolite molecular sieve, to ensure, that water can pass through the membrane, the fluid or the Desiccant but not. In an alternative embodiment is the moisture exchanger as a porous Ceramic tube formed with a zeolite coating. The zeolite coating On the one hand absorbs the moisture, but also allows the passage of moisture. In a preferred embodiment, the ceramic tube is filled with a zeolite granulate, for the storage option for moisture to increase and so a combined moisture filter with integrated moisture exchanger to build. The ceramic is, for example, a PTC ceramic. This has the advantage of being in addition to the carrier function can serve as a heater.

Around the flow of fluid through the bypass line continuously Maintain is preferably the bypass line to a Fluid leading Tube of the closed circuit connected, which is a compressor having. This creates the corresponding pressure gradient, which the necessary flow of the fluid is maintained.

Around to check how effectively the corresponding dehumidifiers have dehumidified the fluid, is in the bypass line, preferably after the first dehumidifier, especially in front of the point at which the fluid in the closed Cycle is returned, arranged a humidity sensor.

Especially Preferably, the fluid is as a refrigerant and / or the closed circuit is designed as a refrigeration system, because straight refrigerant must not have moisture, for a safe function of the refrigeration system to ensure.

The inventive method drying of closed-loop fluids is based on from a fluid-carrying tube of the closed circuit part of the fluid in a parallel to the fluid conducting tube to lead the closed circuit switched bypass line. In the bypass line is a device for drying fluid according to the invention arranged, with which the fluid is deprived of moisture. By Arrangement of the device in a bypass line, it is possible during operation the closed circuit on the one hand to dry the fluid, on the other hand but also a defective device for drying fluid or a Apparatus for drying fluid in which a dehumidifier saturated is while to service and exchange.

at the method according to the invention is preferably in the bypass line, a device for drying of fluid with at least one first dehumidifier, which serves as a moisture filter is formed, and at least one further dehumidifier, which as Moisture exchanger is formed, arranged, of course, the Humidity filter and the moisture exchanger also in a dehumidifier can be arranged integrated. The moisture filter is activated when a defined threshold value is reached heated to expel the moisture collected in the moisture filter and over remove the moisture exchanger. Thereby is enabled that the bypass line is not open Must be to remove the moisture in a dehumidifier in the Bypass line was collected to remove from the bypass line. In particular, thus no fluid, which is in the bypass line located in the area, so no costs for disposal of the fluid arise.

Preferably is in the bypass line a second dehumidifier, which as a moisture filter is formed, which is arranged by the first moisture filter can absorb unfiltered moisture and thus the degree of dryness elevated.

Preferably, a third valve is arranged between the first valve and the first dehumidifier, and a fourth valve is arranged between the second dehumidifier and the second valve, wherein either the first dehumidifier or the second dehumidifier is switchable behind the first valve via the third valve in the flow direction and wherein Alternatively, either the second dehumidifier or first dehumidifier before the second valve is switchable via the fourth valve, so that when flow from the third valve to the fourth valve, either first first dehumidifier and then the second dehumidifier or alternatively first the second dehumidifier and then the first dehumidifier is passed through. This makes it possible to reverse the flow direction. A change in the direction of flow is preferably provided after heating a moisture filter to expel the collected moisture to maximize replacement and most effective Drying of both desiccant and dehumidifiers to ensure.

In a preferred embodiment of the process, the moisture gradient for optimal operation increased by the moisture exchanger, that on the side facing away from the closed circuit of the moisture exchanger arranged a device for generating a moisture gradient is.

The The invention will be explained in detail with reference to the following figures. It shows:

1 a schematic representation of a first embodiment of the invention,

2 a schematic representation of a second embodiment of the invention,

3 a schematic representation of a third embodiment of the invention,

4 a schematic representation of a fourth embodiment of the invention and

5 a schematic representation of a fifth embodiment of the invention.

In the 1 to 5 different embodiments of the invention are shown, wherein like reference numerals designate like components and components.

1 shows a first embodiment of an apparatus for drying fluid guided in a closed circuit. In this case, the closed circuit is designed, for example, as a refrigeration system, in which a refrigerant is conducted as the fluid. In 1 is a pipe 10 , which conducts refrigerant, shown as part of a refrigeration system. In the pipe carrying the refrigerant 10 is a compressor 15 arranged, which maintains the speed of the flow and optionally regulated. Parallel to the pipe 10 is a bypass line 20 arranged, which via a first valve V1 and a second valve V2 to the pipe 10 is connected and via these two valves V1, V2 also completely from the pipe 10 can be disconnected. Via the first valve V1, as soon as this valve V1 is opened, part of the gas flows in the pipe 10 guided refrigerant in the bypass line 20 , The refrigerant flow should be in the bypass line 20 be less than 5% of the total mass flow of refrigerant and in particular not exceed 10% of the total mass flow in order to disturb the refrigerant flow in the refrigeration system as little as possible. Behind the first valve V1 is a throttle valve 24 arranged, which for controlling the mass flow through the bypass line 20 serves. The flow direction of the refrigerant is indicated by the open arrows in 1 displayed.

In the bypass line 20 is arranged a first dehumidifier E1, which is flowed through by the refrigerant. The first dehumidifier may in principle be a moisture exchanger or, as in 1 shown to a moisture filter, in particular a zeolite filter 50 act. This moisture filter has a housing E1a, which is sealed to the outside. Neither refrigerant nor moisture can thus escape from the housing E1a of the first dehumidifier E1. The refrigerant is dried in the first dehumidifier E1, wherein in the zeolite filter 50 the moisture accumulates. The refrigerant thus dried continues to flow through the bypass line 20 in the direction of the second valve V2, behind the second valve V2 back into the pipe 10 to flow into the refrigeration system. Before the refrigerant enters the pipe 10 flows in, in particular in front of the second valve V2, there is a humidity sensor 22 which checks which degree of drying the refrigerant has reached. In particular, with the humidity sensor 22 also the functioning of the first dehumidifier E1 be checked. Because in the first dehumidifier E1, in particular in the zeolite filter 50 , which accumulates moisture, the moisture content of the zeolite filter increases 50 , If the water content in the zeolite filter is too high 50 there is a risk of water leakage. The water content of the zeolite filter 50 must therefore be controlled, preferably via a correspondingly integrated measuring probe. Periodically, the zeolite filter needs 50 be replaced to prevent water leakage. For this purpose, the valves V1, V2 are closed, so that the bypass line 20 can be opened without disturbing the operation of the refrigerant system. Subsequently, the first dehumidifier E1 can be removed and replaced by a new dehumidifier or used again after cleaning and drying. About the control of the water content by means of a humidity sensor 22 or other means for detecting the saturation state of the zeolite filter 50 can by a control of the valves V1, V2, a stop of the flow through the bypass line 20 also be triggered automatically. It is sufficient to close the valve V2.

As in this embodiment, refrigerant, which is in the bypass line 20 is disposed of at additional cost is in a second embodiment of the invention, which in 2 is shown in the bypass line 20 another dehumidifier E5 arranged. Dehumidifier E5 is a moisture exchanger 30 educated. Via a moisture exchanger 30 may moisture over a moisture-impermeable layer, in particular a moisture-permeable membrane 32 , from the system facing the refrigeration system and the Bypasslei tung 20 be removed without the bypass line 20 to open to the outside. Refrigerant can be the moisture-permeable membrane 32 However, do not penetrate, so there is no danger that the refrigerant from the bypass line 20 could escape. The moisture exchanger 30 works in such a way that with a sufficiently high humidity gradient between the two sides of the moisture-permeable membrane 32 Moisture can be diffused through the membrane and dissipated on the other side. The moisture permeable membrane 32 may for example consist of Nafion or zeolite.

In the present second embodiment, via the first dehumidifier E1, the majority in the moisture contained in refrigerant in the zeolite filter 50 to be collected. Optionally, further residual moisture can be removed via the further dehumidifier E5, in particular if the gradient is high enough, for example because the first dehumidifier E1 has reached its saturation level. When the first dehumidifier E1 has reached its saturation level, it is activated via the throttle valve 24 the flow rate greatly throttled and the first dehumidifier E1 heated via a heating port E1b, so that the moisture from the zeolite filter 50 is expelled again. Thus, a large amount of water is released in a short time, which the further dehumidifier E5 downstream of the first dehumidifier E1, ie the moisture exchanger 30 reached. This creates a large gradient on the membrane of the further dehumidifier E5, so that via the moisture exchanger 30 effectively the moisture from the bypass line 20 can be dissipated. After complete heating of the zeolite filter 50 is the zeolite filter 50 again suitable to extract more moisture from the refrigerant, so that the throttle valve 24 can be opened again to increase the flow rate again, and further refrigerant can be dried out of the refrigeration system. The operation of the refrigeration system does not have to be set at any time.

It is essential, however, that care is taken in this embodiment that no concentrated water is returned to the refrigeration system. This could happen if the zeolite filter 50 is heated, the moisture exchanger 30 but not all dissipates water. This is avoided in that the valve V2 and preferably also the valve V1 are completely closed during the baking process. As it burns out in the bypass line 20 it may be necessary to provide a pressure compensation valve when the valves V1, V2 are closed. Alternatively, the humidity exchanger 30 a second dehumidifier, which, like the first dehumidifier E1, is designed as a moisture filter, is connected downstream, which supplies the refrigerant with the moisture which is not via the moisture exchanger 30 is discharged, deprives.

Particularly preferred is the moisture exchanger 30 integrated into the first dehumidifier E1 in order to be able to more effectively remove the moisture from the refrigerant.

3 shows a third embodiment of an apparatus for drying of refrigeration systems, wherein the same parts as in the embodiments according to 1 and 2 are again denoted by the same reference numerals.

In the bypass line 20 is the first dehumidifier E1, a second dehumidifier E2 and between the two dehumidifiers E1, E2, the further dehumidifier E5, which as a moisture exchanger 30 is formed, arranged. The first dehumidifier E1 and the second dehumidifier E2 are used as moisture filters, in particular as zeolite filters 50 educated. In particular, the second dehumidifier E1 also has a housing E1a and a heating connection E1b. In the direction of flow along the open arrows, starting from the first valve V1, first the first dehumidifier E1, then the moisture exchanger 30 and then the second dehumidifier E2 flows through before the refrigerant through the second valve V2 back into the pipe 10 the refrigeration system is transferred. In this embodiment, however, a third valve V3 between the first valve V1 and the first dehumidifier E1 and a fourth valve V4 between the second dehumidifier E2 and the second valve V2 are additionally arranged. The third V3 and the fourth valve V4 are three-way valves, so that via the third valve V3 alternatively either the first dehumidifier E1 or the second dehumidifier E2 behind the first valve V1 and the fourth valve V4 alternatively the second dehumidifier E2 or the first dehumidifier E1 can be switched in front of the second valve V2. This makes it possible, the Strö flow direction between the third valve V3 and the fourth valve V4 through the bypass line 20 to reverse, so either along the open arrows in 3 first the first dehumidifier E2 and then the second dehumidifier E2 or alternatively along the closed arrows in 3 first, the second dehumidifier E2 and then the first dehumidifier E1 is flowed through with the refrigerant. In particular in combination with the arranged between the two dehumidifiers E1, E2 additional moisture exchanger 30 This results in the following preferred operation. First, the refrigerant flows along the open arrows first through the first dehumidifier E1, in which the majority of the moisture contained in the refrigerant through the zeolite filter 50 is removed from the refrigerant. This moisture is in the zeolite filter 50 saved. Residual moisture can either via the additional moisture exchanger 30 if the moisture gradient is large enough, or over the second dehumidifier E2 be effectively removed from the refrigerant, so that an increased degree of drying of the refrigerant is achieved. About the humidity sensor 22 the humidity of the refrigerant is checked. Thus or with the aid of additional measuring probes at the dehumidifiers E1, E2 it can be checked which degree of saturation of the first dehumidifier E1 has already been reached. If the corresponding degree of saturation of the dehumidifier E1 is reached, can through the throttle valve 24 the refrigerant flow rate can be reduced or stopped by throttling, wherein also the first valve V1 and the second valve V2 can optionally be closed for increased safety. Subsequently, the first dehumidifier E1 is heated via the heating connection E1b, for example to about 200 ° C. By heating, the collected water from the zeolite filter 50 of the first dehumidifier E1 and expelled to the moisture exchanger 30 transported. There is now a sufficiently large moisture gradient to effectively transfer the water through the moisture exchanger 30 dissipate. If appropriate, residual moisture remaining in the refrigerant is taken up via the second dehumidifier E2. After the first dehumidifier E1 has been dried in this way, the third valves V3 and the fourth valve V4 are now transferred in such a way that subsequently the flow through the bypass line along the closed arrows and thus in the opposite flow direction through the section of the bypass line 20 between the third valve V3 and the fourth valve V4 runs, so that initially the second dehumidifier E2 then the additional moisture exchanger 30 and finally the first dehumidifier E1 are flowed through by the refrigerant. As a result, the second dehumidifier E2 is now predominantly loaded with water from the refrigerant, while the additional moisture exchanger 30 hardly comes into function and the first dehumidifier E1 absorbs the residual moisture from the refrigerant. In this way, a maximum exchange and the most effective degree of drying of the refrigerant and a high degree of drying of the dehumidifier E1, E2 can be achieved without the bypass line 20 or even having to open the refrigeration system. In particular, the operation of the refrigeration system does not have to be adjusted.

About the moisture exchanger 30 will be in the in 3 illustrated embodiments, the water discharged such that it, for example, from the moisture-permeable membrane 32 dripped out or outgassed. The membrane 32 is designed such that it is permeable only to water, but not for the refrigerant flowing in the refrigeration system, and may for example be made of Nafion or formed as a zeolite molecular sieve.

To the moisture gradient over the membrane 32 can increase, for example, on the side facing away from the refrigeration system of the membrane 32 a device for generating negative pressure can be arranged so that the moisture gradient increases and more water through the membrane 32 steps outward. Alternatively, a drying agent on the side facing away from the refrigeration system of the membrane 32 are passed to increase the humidity gradient. This can be achieved, for example, with a fifth embodiment of the invention as shown in FIG 5 is shown. In this embodiment, on the side facing away from the refrigeration system of the membrane 32 a desiccant feeder arranged, for example, alternatively in the provision of a compressed gas such as nitrogen or air via a gas supply 41 or in an ambient air supply 42 can exist with the help of a suitable compressor. The desiccant feeder 40 performs the appropriate desiccant, such as the gas such as nitrogen or the air on the side facing away from the refrigeration system of the membrane 32 the additional humidity exchanger 30 passing in a desiccant removal 44 , In order to keep the desiccant in a cycle, this can be done in desiccant removal 44 arrived desiccant the desiccant feeder are fed back. However, the desiccant can be removed only after a single use.

Between the desiccant feeder 40 and the membrane 32 a third dehumidifier E3 is arranged, which preferably also as a moisture filter, in particular zeolite filter 50 , is trained. In this case, the third dehumidifier E3 has a housing E3a and a heating connection E3b. In the zeolite filter 50 the added desiccant is additionally dehumidified before it reaches the membrane 32 is guided to the moisture gradient across the membrane 32 continue to increase.

Preferably, between the membrane 32 and desiccant removal 44 a fourth dehumidifier E4 arranged, in particular also as a moisture filter, in particular as a zeolite filter 50 is trained. In this case, the fourth dehumidifier E4 has a housing E4a and a heating connection E4b.

Between the desiccant feeder 40 and the third dehumidifier E3, a fifth valve V5 is disposed, while between the fourth dehumidifier E4 and desiccant discharge 44 a sixth valve V6 is arranged. The fifth valve V5 and the sixth valve V6 are also designed as a three-way valve, so that via the fifth valve V5 alternatively the third dehumidifier E3 or the fourth dehumidifier E4 behind the desiccant feed device 40 can be switched, while via the sixth valve V6 alternatively the fourth dehumidifier E4 or the third dehumidifier E3 before Tro ckenmittelabfuhr 44 can be switched. As a result, a reversal of the flow direction through the desiccant circuit is again possible in this arrangement, as indicated by the open or closed arrows. Furthermore, the third dehumidifier E3 and the fourth dehumidifier E4 are designed to be heated. As a result, the following process for drying the desiccant and drying the third dehumidifier E3 and the fourth dehumidifier E4 is possible. First, about the desiccant feeder 40 along the open arrows the desiccant in the first dehumidifier E3 out where the desiccant is dehumidified, so that the third dehumidifier E3 is loaded with moisture. At the membrane 32 However, the desiccant in turn absorbs moisture, which can be filtered out in the fourth dehumidifier E4, if the desiccant back to the membrane 32 led who should. Alternatively, that of the membrane 32 downstream dehumidifiers E4 are heated in addition to let through the moisture absorbed by the desiccant and expel the moisture already absorbed. An additional valve can alternatively also the respective membrane 32 Downstream dehumidifiers E3, E4 are completely switched off from the desiccant flow in order to save heating costs in this way. In principle, it is thus also possible to arrange only one dehumidifier in the desiccant circuit.

If one of the two dehumidifiers E3, E4 reaches its saturation level, the valves V5, V6 are switched such that the corresponding dehumidifier E3, E4 is in front of the desiccant discharge 44 is switched. The corresponding dehumidifier E3, E4 is then heated, so that the moisture in the direction of desiccant removal 44 can be dissipated without the membrane 32 To be passed and where appropriate to cause moisture in the bypass line 20 is registered.

A fourth embodiment of the invention is in 4 shown. In this embodiment, in the bypass line 20 a first dehumidifier E1 'and a second dehumidifier E2' arranged. In the direction of flow along the open arrows, the refrigerant firstly flows from the first valve V1 through the first dehumidifier E1 'and then through the second dehumidifier E2', before it returns via the second valve V2 into the pipe carrying the refrigerant 10 the cooling system is supplied. Between the first dehumidifier E1 'and the first valve V1, in turn, the third valve V3 designed as a three-way valve is arranged, via which alternatively the first dehumidifier E1' or the second dehumidifier E2 'can be connected behind the first valve V1. Between the second dehumidifier E2 'and the second valve V2' is again designed as a three-way valve fourth valve V4 arranged, via which alternatively the first dehumidifier E1 'or the second dehumidifier E2' can be switched in front of the second valve V2, so that at corresponding Circuit of the two valves V3, V4, the flow direction can be reversed such that between the two valves V3, V4, the flow along the closed arrows in the reverse direction, first by the second dehumidifier E2 'and then by the first dehumidifier E1' can be done.

The two dehumidifiers E1 ', E2' are as a porous ceramic tube 52 with a zeolite coating 54 on the inside of the ceramic tube 52 fitted. The zeolite coating ensures that only water through the ceramic tube 52 can pass through, but the refrigerant within the zeolite coating 54 through the ceramic tube 52 flows and thus not from the bypass line 20 can escape. The ceramic tube thus essentially serves as a carrier ceramic for the zeolite coating 54 , If, for example, a PTC ceramic is used as the carrier ceramic, it can additionally be used as a heater. The zeolite coating 54 essentially acts as a moisture exchanger.

The first dehumidifier E1 'and the second dehumidifier E2' are located in a chamber 70 in which the through the zeolite coating 54 collected moisture collected and which preferably during heating via a pump 60 is emptied to a sufficiently high moisture gradient at the zeolite coating 54 provide. In particular, while the moisture in a container 62 drip and over the pump 60 be removed. In normal operation, the pump must 60 not necessarily run permanently. But then to prevent moisture from the container 62 back into the refrigerant through the zeolite coating is preferably between the chamber 70 and the container 62 arranged a valve which is closed during operation and is open only during the heating phases. Because before closing the valve by the pump 60 a negative pressure in the chamber 70 is generated, there is only a very small proportion of air in the chamber 70 which does not cause any significant entry of moisture back into the refrigerant during operation.

The chamber 70 Alternatively, during normal operation, it may be rinsed with dry air or other desiccant to reduce the moisture gradient on the zeolite coating 54 sufficiently high. In this case, in particular, the air in turn with a device comparable to the side facing away from the refrigeration system of the membrane 32 of the moisture exchanger 30 of the embodiment in 5 be dried device shown.

The chamber 70 For its part, it can also have a water-permeable membrane, which on the side facing away from the dehumidifier E1 ', E2' can be equipped with a corresponding device for increasing the moisture gradient, so that the chamber 70 represents an additional protective wall, if by the zeolite coating 54 Refrigerant should escape. Should have pores in the zeolite coating 54 lead to a refrigerant passage, this is for example by an increase in pressure in the chamber 70 recognizable during the drying phase, so that the leaked refrigerant via another in the chamber 70 arranged dehumidifier, not shown, could be sucked dry and collected.

In order to further increase the degree of dryness of the dehumidifiers E1 ', E2' is in the ceramic tube 52 a zeolite granulate 56 arranged, which is flowed around by the refrigerant while removing moisture from the refrigerant. Since the zeolite granules 56 thus acts as a moisture filter, in this embodiment, the dehumidifier E1 ', E2' is a moisture filter with integrated moisture exchanger. Reaches the zeolite granules 56 saturation, the first dehumidifier E1 'and the second dehumidifier E2' may in turn be designed to be heatable in order to specifically control the moisture via the zeolite coating 54 to surrender to the outside.

10

pipe

15

compressor

20

bypass line

22

humidity sensor

24

throttle valve

V1

first Valve

V2

second Valve

V3

third Valve

V4

fourth Valve

V5

fifth valve

V6

sixth Valve

E1

first dehumidifiers

E1 '

first dehumidifiers

e1a

casing

e1b

heating connection

E2

second dehumidifiers

E2 '

second dehumidifiers

E2a

casing

E2b

heating connection

E3

third dehumidifiers

E3a

casing

e3b

heating connection

E4

fourth dehumidifiers

E4a

casing

E4b

heating connection

E5

fifth dehumidifier

30

moisture exchanger

32

membrane

40

Desiccant feeder

41

gas supply

42

Ambient air

44

Desiccant dissipation

50

Zeolithfilter

52

ceramic tube

54

zeolite coating

56

zeolite granules

60

pump

62

container

70

chamber

Claims (31)

Device for drying fluids circulated in closed circuits with a bypass line ( 20 ), which via a first valve (V1) and a second valve (V2) parallel to a fluid-carrying tube ( 10 ) of the closed circuit is switchable, wherein in the bypass line ( 20 ) a first dehumidifier (E1) is arranged. Device according to one of the preceding claims, characterized in that in the bypass line ( 20 ) behind the first dehumidifier (E1), a second dehumidifier (E2, E5) is arranged. Device according to claim 2, characterized in that that between the first valve (V1) and the first dehumidifier (E1) a third valve (V3) and between the second dehumidifier (E2) and the second valve (V2), a fourth valve (V4) is arranged is, being over the third valve (V3) in the flow direction either the first dehumidifier (E1) or the second dehumidifier (E2) behind the first valve (V1) is switchable and wherein over the fourth valve alternatively either the second dehumidifier (E2) or the first (E1) dehumidifier can be switched in front of the second valve (V2) is, so with flow from the third valve (V3) to the fourth valve (V4), either first first dehumidifier (E1) and then the second dehumidifier (E2) or alternatively first the second dehumidifier (E2) and then the first (E1) dehumidifier flows through becomes. Device according to one of the preceding claims, characterized in that the first dehumidifier (E1) and / or the second Dehumidifiers (E2, E5) are designed as moisture exchangers. Device according to one of claims 1 to 4, characterized that the first dehumidifier (E1) and / or the second dehumidifier (E2) are designed as moisture filters. Device according to one of claims 1 to 4, characterized that the first dehumidifier (E1) and / or the second dehumidifier (E2) are designed as a moisture filter with integrated moisture exchanger. Device according to one of claims 1 to 4, characterized that the first dehumidifier (E1) as a moisture filter and the second Dehumidifiers (E2, E5) are designed as moisture exchangers. Device according to one of claims 1 to 4, characterized in that the first dehumidifier (E1) and the second dehumidifier (E2) are formed as a moisture filter and between the two moisture filters another dehumidifier (E5) is arranged, which as a moisture exchanger ( 30 ) is trained. Device according to one of claims 4, 6, 7 or 8, characterized in that on the side facing away from the closed circuit of the moisture exchanger ( 30 ) a device for generating a moisture gradient is arranged. Device according to claim 9, characterized in that that the device for generating a moisture gradient as a Device is designed for generating a negative pressure. Apparatus according to claim 9, characterized in that the device for generating a moisture gradient as a desiccant feed device ( 40 ) is formed, which a desiccant on the moisture exchanger ( 30 ) into a desiccant removal ( 44 ) leads. Apparatus according to claim 11, characterized in that between the desiccant feed device ( 40 ) and the moisture exchanger ( 30 ) a third dehumidifier (E3) is arranged. Apparatus according to claim 11 or 12, characterized in that between the moisture exchanger ( 30 ) and desiccant removal ( 44 ) a fourth dehumidifier (E4) is arranged. Apparatus according to claim 12 and 13, characterized in that between the desiccant feed device ( 40 ) and the third dehumidifier (E3) a fifth valve (V5) and between the fourth dehumidifier (E4) and desiccant removal ( 44 ) a sixth valve (V6) is arranged, wherein via the fifth valve (V5) in the flow direction either the third dehumidifier (E3) or the fourth dehumidifier (E4) behind the desiccant feed device ( 40 ) and wherein via the sixth valve (V6) alternatively either the fourth dehumidifier (E4) or the third dehumidifier (E3) before the desiccant discharge ( 44 ) is switchable, so that when flow from the desiccant feeder ( 40 ) to the desiccant removal ( 44 ) either first the third dehumidifier (E3) and then the fourth dehumidifier (E4) or alternatively first the fourth dehumidifier (E4) and then the third dehumidifier (E3) is flowed through. Device according to one of claims 12 to 14, characterized that the third dehumidifier (E3) and / or the fourth dehumidifier (E4) are designed as moisture filters. Device according to one of claims 4 to 15, characterized in that the moisture filter as a zeolite filter ( 50 ) are formed. Device according to one of the preceding claims, characterized in that the first dehumidifier (E1) and / or the second Dehumidifier (E2, E5) and / or the third dehumidifier (E3) and / or the fourth dehumidifier (E4) and / or the further dehumidifier (E5) are heated. Device according to one of the preceding claims, characterized in that the additional moisture exchanger ( 30 ) is heated. Device according to one of the preceding claims, characterized in that the moisture exchanger ( 30 ) is designed as a moisture-permeable membrane, in particular as a Nafion membrane or as a zeolite molecular sieve. Device according to one of the preceding claims, characterized in that the moisture exchanger ( 30 ) as a porous ceramic tube ( 52 ) with a zeolite coating ( 54 ) is trained. Device according to claim 20, characterized in that the ceramic tube ( 52 ) with a zeolite granulate ( 56 ) is filled. Apparatus according to claim 21, characterized in that the ceramic tube ( 52 ) is made of a PTC ceramic. Device according to one of the preceding claims, characterized in that in the fluid-carrying tube ( 10 ) of the closed circuit a compressor ( 15 ) is arranged. Device according to one of the preceding claims, characterized in that in the bypass line ( 20 ), preferably after the first dehumidifier (E1), a humidity sensor ( 22 ) is arranged. Device according to one of the preceding claims, characterized characterized in that the fluid is a refrigerant and / or the closed Cycle a refrigeration system is. Process for drying fluids circulating in closed circuits, in which a fluid-carrying tube ( 10 ) of the closed circuit part of the fluid in a parallel to the fluid-carrying tube ( 10 ) of the closed circuit switched bypass line ( 20 ) guided is and where in the bypass line ( 20 ) a device for drying fluids according to one of the preceding claims is arranged. Process for drying fluids circulating in closed circuits, in which a fluid-carrying tube ( 10 ) of the closed circuit, a portion of the fluid in a via a first valve (V1) and a second valve (V2) parallel to the fluid-carrying tube ( 10 ) of the closed circuit switched bypass line ( 20 ) and wherein in the bypass line, a device for drying fluid with at least a first dehumidifier (E1), which is designed as a moisture filter, and at least one second dehumidifier (E2, E5), which as a moisture exchanger ( 30 ) is formed, and wherein the moisture filter is heated when a defined threshold value is reached in order to drive out the moisture collected in the moisture filter and via the moisture exchanger ( 30 ) dissipate. A method according to claim 27, characterized in that in the bypass line ( 20 ) a second dehumidifier (E2), which is preferably designed as a moisture filter, is arranged. Method according to Claim 28, characterized that between the first valve (V1) and the first dehumidifier (E1) a third valve (V3) and between the second dehumidifier (E2) and the second valve (V2), a fourth valve (V4) is arranged is, being over the third valve (V3) in the flow direction either the first dehumidifier (E1) or the second dehumidifier (E2) behind the first valve (V1) is switchable and wherein over the fourth valve (V4) alternatively either the second dehumidifier (E2) or the first dehumidifier (Ei) switchable in front of the second valve (V2) is, so with flow from the third valve (V3) to the fourth valve (V4) either first the first dehumidifier (E1) and then the second dehumidifier (E2) or alternatively the first second dehumidifier (E2) and then the first dehumidifier (E1) is flowed through. Method according to claim 29, characterized after heating a dehumidifier (Ei, E2) to expel the Moisture collected the flow direction is changed. Method according to one of claims 27 to 30, characterized in that on the side facing away from the closed circuit of the moisture exchanger ( 30 ) a device for generating a moisture gradient is arranged.